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DOE OSTI2025

Resonant inelastic x-ray scattering investigation of Hund's and spin-orbit coupling in 5 d 2 double perovskites

𝐵 site ordered 5⁢𝑑 2 double perovskites (𝐴 2 ⁢𝐵⁢𝐵′⁢O 6 , 𝐵′ = 5⁢𝑑 2 ) display a remarkable range of physical properties upon variation of the chosen 𝐵 and 𝐵′ site ions. This sensitivity to chemical substitution reflects the delicate balance and profound impact of strong electronic correlation and spin-orbit coupling in such systems. Here, we present rhenium 𝐿 2 and 𝐿 3 resonant inelastic x-ray scattering (RIXS) measurements of two such physically dissimilar materials, Mott-insultating Ba 2⁢ Y⁢Re⁢O 6 and semiconducting Sr 2⁢ Cr⁢Re⁢O 6 . Despite these differences, our RIXS results reveal similar energy scales of Hund's (𝐽 𝐻 ) and spin-orbit coupling (𝜁) in the two materials, with both systems firmly in the intermediate Hund's coupling regime where 𝐽 𝐻 /𝜁∼1. However, there are clear differences in their RIXS spectra. The conductive character of Sr 2⁢ Cr⁢Re⁢O 6 broadens and obfuscates the atomic transitions within an electron-hole continuum, while the insulating character of Ba 2 ⁢Y⁢Re⁢O 6 results in sharp atomic excitations. This contrast in their RIXS spectra despite their similar energy scales reflects a difference in the itinerancy-promoting hopping integral and illustrates the impact of the local crystal environment in double perovskites. Finally, 𝐿 2 and 𝐿 3 edge analyses of the atomic excitations in Ba 2 ⁢Y⁢Re⁢O 6 reveal that the ordering of the low lying excited states is inverted compared to previous reports, such that the appropriate energy scales of Hund's and spin-orbit coupling are significantly modified. We present exact diagonalization calculations of the RIXS spectra at both edges which show good agreement with our results for new energy scales of 𝜁 = 0.290⁢(5)⁢eV and 𝐽 𝐻 = 0.38⁢(2)⁢eV [𝐽 𝐻 /𝜁 = 1.30⁢(5)].

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2018

Minimum Energy of Multicomponent Distillation Systems Using Minimum Additional Heat and Mass Integration Sections

Heat and mass integration to consolidate distillation columns in a multicomponent distillation configuration can lead to a number of new energy efficient and cost effective configurations. In this paper, we identify a powerful and simple-to-use fact about heat and mass integration. The newly developed heat and mass integrated configurations, which we call as HMP configurations, involve first introducing thermal couplings to all intermediate transfer streams, followed by consolidating columns associated with a lighter pure product reboiler and a heavier pure product condenser. A systematic method of enumerating all HMP configurations is introduced. We compare the energy savings of HMP configurations with the well-known fully thermally coupled (FTC) configurations. We demonstrate that HMP configurations can have very similar and sometimes even the same minimum total vapor duty requirement as the FTC configuration, while using far less number of column sections, intermediate transfer streams, and thermal couplings than the FTC configurations.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2013

Efficient near-field wireless energy transfer using adiabatic system variations

Disclosed is a method for transferring energy wirelessly including transferring energy wirelessly from a first resonator structure to an intermediate resonator structure, wherein the coupling rate between the first resonator structure and the intermediate resonator structure is .kappa..sub.1B, transferring energy wirelessly from the intermediate resonator structure to a second resonator structure, wherein the coupling rate between the intermediate resonator structure and the second resonator structure is .kappa..sub.B2, and during the wireless energy transfers, adjusting at least one of the coupling rates .kappa..sub.1B and .kappa..sub.B2 to reduce energy accumulation in the intermediate resonator structure and improve wireless energy transfer from the first resonator structure to the second resonator structure through the intermediate resonator structure.

42 ENGINEERING↗

DOE OSTI2014

Efficient near-field wireless energy transfer using adiabatic system variations

42 ENGINEERING↗

DOE OSTI2017

Efficient near-field wireless energy transfer using adiabatic system variations

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2014

Excitation of the 3p states in electron-sodium scattering at intermediate energies

A coupled-channel-optical method (CCOM), to investigate the excitation of the 3p states for e{sup −}-Na scattering at intermediate energies, is reported. Nine atomic states( Na(3s), Na(3p), Na(4s), Na(3d), Na(4p), Na(5s), Na(4d), Na(5p), Na(5d) ) together with three optical potentials are used in this work. The inelastic differential cross sections (DCS) as well as the reduced Stokes parameters are compared with latest theoretical data and experimental measurements.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2016

Electrochemical Detection of Transient Cobalt Hydride Intermediates of Electrocatalytic Hydrogen Production

We report the use of variable scan rate cyclic voltammetry to detect transient CoIIIH and CoIIH intermediates of electrocatalytic H2 production by CoII(dmgBF2)2(CH3CN)2 and [CoII(PtBu2NPh2)(CH3CN)3]2+. In both cases, reduction of the CoIIIH intermediate was observed to coincide with the CoII/I couple, and the resulting CoIIH intermediate is protonated by acid to afford H2. Our studies indicate that in electrocatalytic H2 production, protonation of CoIIH is rate-limiting for CoII(dmgBF2)2(CH3CN)2, and protonation of CoI is rate-limiting for [CoII(PtBu2NPh2)(CH3CN)3]2+. This research was supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences. Pacific Northwest National Laboratory is operated by Battelle for the U.S. Department of Energy.

cobalt, electrocatalysis, hydrogen↗

DOE OSTI2019

Process Intensification in Multicomponent Distillation: A Review of Recent Advancements

Process Intensification (PI) is an emerging concept in chemical engineering that describes the design innovations that lead to significant shrinkage in size and boost in efficiency of a process plant. Distillation, the most commonly used separation technique in the chemical industry, is a crucial component of PI. We systematically discuss the following aspects of PI in non-azeotropic multicomponent distillation: 1) Introducing thermal couplings to eliminate intermediate reboilers and condensers to save energy and capital cost; 2) Improving operability of thermally coupled columns by means of eliminating vapor streams in thermal couplings with only liquid transfers or column section rearrangement; 3) Enabling double and multi-effect distillation of thermally coupled configurations to further reduce heat duty; 4) Performing simultaneous heat and mass integration among thermally coupled columns to reduce the number of columns and heat duty; and 5) Conducting any thermally coupled distillation in n-product streams using 1 to n - 2 column shells with operable novel dividing wall columns. We demonstrate these aspects of PI through examples to illustrate how they lead to compact, easy-to-operate, energy efficient and cost effective multicomponent distillation system designs.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2022

Evidence for H-bonding interactions to the μ-η 2 :η 2 -peroxide of oxy-tyrosinase that activate its coupled binuclear copper site

The factors that control the diverse reactivity of the μ-η 2 :η 2 -peroxo dicopper(II) oxy-intermediates in the coupled binuclear copper proteins remain elusive. In this study, spectroscopic and computational methods reveal H-bonding interactions between active-site waters and the μ-η 2 :η2-peroxide of oxy-tyrosinase, and define their effects on the Cu(II) 2 O 2 electronic structure and O 2 activation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2023

Understanding Dynamics and Thermodynamics of ENSO and Its Complexity Simulated by E3SM and Other Climate Models

Despite the seeming success of most state-of-the-art climate models in simulating the El Niño-Southern Oscillation (ENSO), there is strong evidence that models achieve realistic levels of ENSO activity do so often for wrong reasons. This is owing to an often occurred near cancelation of large errors in terms of contributions to ENSO growth rate from coupled dynamic and thermodynamic feedback processes. Climate models remain deficient in simulating the observed ENSO’s spatial and temporal complexity that involves interplays of coupled dynamic and thermodynamic feedbacks, interactions across multiple scales, nonlinear processes in the tropical atmosphere and ocean system, biases in mean sate and physical processes, and influences external to equatorial Pacific coupled ENSO dynamics. Our proposed research aims at advancing predictive and process-level understandings of ENSO simulated in E3SM and other climate models under current and future climate conditions with two main objectives: (i) better understanding the aforementioned broad range interactive processes and sources that control fundamental properties of ENSO in E3SM and CIMP6 outputs as well as in observational (reanalysis) data sets, using a hierarchical of coupled dynamical frameworks consisting of theoretical analysis, intermediate complexity modeling, and coupled dynamic diagnostics; (ii) to use this understanding to explore pathways towards improving E3SM’s capability of simulating ENSO and its complexity. More specifically, we will focus on four main thrusts of research: (1) ENSO’s dynamic and thermodynamic feedbacks; (2) the across-scale interactions of ENSO with annual cycle and MJO/WWB/TIW (Madden Julian Oscillation/Westerly Wind Burst/Tropical Instability Wave) activity; (3) key nonlinear processes of ENSO involving atmospheric convective thresholds, nonlinear ocean dynamic heating, and thermocline outcropping; and (4) the impacts of climate mean-state biases/changes and perturbed physical processes on simulated ENSO and its complexity.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2025

Olefin Coupling Catalyzed by (Pybox)Os Complexes via Osmacyclopentane Intermediates: Comparison with Isoelectronic (Phebox)Ir

(Pybox)Os is found to catalyze alkene hydrovinylation, effecting the dimerization of ethylene, tail-to-tail coupling of propene and 1-butene, and cross-coupling of ethylene with higher α-olefins. This reactivity contrasts with the previously reported dehydrogenative coupling of ethylene to give butadiene catalyzed by the isoelectronic fragment (Phebox)Ir. The reaction mechanism was investigated through computational and experimental means. Both the Os- and Ir-catalyzed reactions proceed through a [2 + 2 + 1] cyclization of the corresponding bis-olefin complex to yield an experimentally observed metallacyclopentane intermediate. In both cases, the metallacyclopentane undergoes β- H elimination, via a dechelated κ 2 -pincer-ligated intermediate, to yield a σ−π-but-3-enyl hydride complex or derivative. Both the greater reactivity and the distinct chemoselectivity of the Os system relative to the Ir system are attributable to C−H reductive elimination by the σ−π-but-3-enyl hydride having a barrier for Os much lower than that for Ir. This lower barrier to C−H elimination for Os is unexpected given that the thermodynamic driving force for elimination is much less for Os than for Ir. Computational studies of model complexes were conducted, comparing (Pybox)Os(L)(CH 3 )(H) with the isoelectronic (Phebox)Ir(L)(CH 3 )(H). The results indicate that the more facile kinetics with Os relative to Ir may be general for C−H elimination from six-coordinate d 6 complexes of the two metals, as well as for the microscopic reverse, i.e., C−H addition to the corresponding four-coordinate d 8 species.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2021

Spectroscopic Evidence of Hyponitrite Radical Intermediate in NO Disproportionation at a MOF‐Supported Mononuclear Copper Site

Abstract Dianionic hyponitrite (N 2 O 2 2− ) is often proposed, based on model complexes, as the key intermediate in reductive coupling of nitric oxide to nitrous oxide at the bimetallic active sites of heme‐copper oxidases and nitric oxide reductases. In this work, we examine the gas‐solid reaction of nitric oxide with the metal–organic framework Cu I ‐ZrTpmC* with a suite of in situ spectroscopies and density functional theory simulations, and identify an unusual chelating N 2 O 2 .− intermediate. These results highlight the advantage provided by site‐isolation in metal–organic frameworks (MOFs) for studying important reaction intermediates, and provide a mechanistic scenario compatible with the proposed one‐electron couple in these enzymes.

Sun, Chenyue↗

DOE OSTI2021

Spectroscopic Evidence of Hyponitrite Radical Intermediate in NO Disproportionation at a MOF-Supported Mononuclear Copper Site

Dianionic hyponitrite (N 2 O 2 2- ) is often proposed, based on model complexes, as the key intermediate in reductive coupling of nitric oxide to nitrous oxide at the bimetallic active sites of heme-copper oxidases and nitric oxide reductases. In this work, we examine the gas-solid reaction of nitric oxide with the metal–organic framework Cu I -ZrTpmC* with a suite of in situ spectroscopies and density functional theory simulations, and identify an unusual chelating N 2 O 2 .- intermediate. These results highlight the advantage provided by site-isolation in metal–organic frameworks (MOFs) for studying important reaction intermediates, and provide a mechanistic scenario compatible with the proposed one-electron couple in these enzymes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2011

Trapped Two-Dimensional Condensates with Synthetic Spin-Orbit Coupling

We study trapped 2D atomic Bose-Einstein condensates with spin-independent interactions in the presence of an isotropic spin-orbit coupling, showing that a rich physics results from the nontrivial interplay between spin-orbit coupling, confinement and interatomic interactions. For low interactions two types of half-vortex solutions with different winding occur, whereas strong-enough repulsive interactions result in a stripe-phase similar to that predicted for homogeneous condensates. Intermediate interaction regimes are characterized for large enough spin-orbit coupling by an hexagonally-symmetric phase with a triangular lattice of density minima similar to that observed in rapidly rotating condensates.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2018

Energy Decomposition Analysis for Excimers Using Absolutely Localized Molecular Orbitals within Time-Dependent Density Functional Theory and Configuration Interaction with Single Excitations

Here, we present an improved energy decomposition analysis (EDA) scheme for understanding intermolecular interactions in delocalized excited states, especially in excimers. In the EDA procedure, excited states are treated with linear response theory such as configuration interaction singles (CIS) or time-dependent density functional theory (TDDFT), and absolutely localized molecular orbitals (ALMOs) are used to define the intermediate (frozen, excitonic coupling, and polarized) states. The intermolecular interaction energy is thereby separated into frozen, excitonic splitting, polarization, and charge transfer contributions. The excitonic splitting term describes the delocalization effect as two or more degenerate local excitations coupled with each other, which is often an important binding force in excimers. A maximum overlap state-tracking procedure is introduced to connect the initial fragment excitations to the constrained intermediate states and finally to the unconstrained delocalized states of the complex. The EDA scheme is applied to several excimer systems, including the He 2 * and Ne 2 * noble gas excimers, the doubly hydrogen-bonded 2-pyridone dimer, and the aromatic benzene and perylene excimers. We are able to gain some useful insights into the role each term is playing in the formation of these excimers, and the resulting method may also be useful for understanding a range of other complexes in excited states.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2016

Methods and apparatus for use with extreme ultraviolet light having contamination protection

An apparatus for use with extreme ultraviolet (EUV) light comprising A) a duct having a first end opening, a second end opening and an intermediate opening intermediate the first end opening the second end opening, B) an optical component disposed to receive EUV light from the second end opening or to send light through the second end opening, and C) a source of low pressure gas at a first pressure to flow through the duct, the gas having a high transmission of EUV light, fluidly coupled to the intermediate opening. In addition to or rather than gas flow the apparatus may have A) a low pressure gas with a heat control unit thermally coupled to at least one of the duct and the optical component and/or B) a voltage device to generate voltage between a first portion and a second portion of the duet with a grounded insulative portion therebetween.

36 MATERIALS SCIENCE↗

NASA NTRS2019

Assessment of Satellite Sea Surface Salinity Products Using a Coupled ENSO Prediction Model

Much work has gone into revising and updating algorithms for converting satellite-measured radiances to useful ocean variables like sea surface salinity (e.g. SMOS - Boutin et al., 2017, SMAP - Fore et al., 2016 and Aquarius - Meissner et al., 2018). As part of our Ocean Salinity Science Team work, we utilize an intermediate-complexity air/sea coupled model as a transfer function to test if more mature satellite SSS model algorithms actually improve ENSO forecast skill. For initialization of the coupled forecast, we demonstrate that the positive impact of SSS assimilation is brought about by surface freshening near the eastern edge of the western Pacific warm pool and density changes that lead to shallower mixed layer between 10S-5N. In addition, salting near the ITCZ leads to a deepening of the mixed layer and thermocline near 8N. These patterns together provide the background state to amplify equatorial Kelvin waves and improve ENSO hindcasts (Hackert et al., 2019). Here we extend this work to compare the impact of various pairs of original and improved satellite SSS algorithms. For instance we compare SMAP V4.1 with the latest, SMAP V4.2, to see what impact algorithm improvements may have on ENSO forecasts. SSS observations are tested on seasonal to interannual variability of tropical Indo-Pacific Ocean dynamics as well as on dynamical ENSO forecasts by initializing twelve-month forecasts for each month of available data. All experiments assimilate satellite sea level (SL), sea surface temperature (SST), and in situ subsurface temperature and salinity observations (Tz, Sz). Additionally various satellite, blended, and in-situ SSS products are assimilated. We find that including satellite SSS significantly improves NiÃ±o3.4 sea surface temperature anomaly validation, more mature SSS model algorithms are generally improving ENSO forecasts over time, and more satellite SSS data coverage helps to extend useful forecasts.

Ocean↗

DOE OSTI2021

Origin of Chirality Induced Spin Selectivity in Photoinduced Electron Transfer

Here we propose a mechanism by which spin-polarization can be generated dynamically in chiral molecular systems undergoing photoinduced electron transfer. The proposed mechanism explains how spin-polarization emerges in systems where charge transport is dominated by incoherent hopping, mediated by spin-orbit and electronic exchange couplings through an intermediate charge transfer state. We derive a simple expression for the spin-polarization that predicts a nonmonotonic temperature dependence, consistent with recent experiments, and a maximum spin-polarization that is independent of the magnitude of the spin-orbit coupling. We validate this theory using approximate quantum master equations and the numerically exact hierarchical equations of motion. The proposed mechanism of chirality induced spin selectivity should apply to many chiral systems, and the ideas presented here have implications for the study of spin transport at temperatures relevant to biology and provide simple principles for the molecular control of spins in fluctuating environments.

77 NANOSCIENCE AND NANOTECHNOLOGY↗